Rack for diagnostic diffusion plates

ABSTRACT

The attached specification discloses a rack for retaining a plurality of diagnostic diffusion plates in assembled relation. The rack preferably is made of injection molded plastic and is of rectangular shape. It comprises a bottom formed with a plurality of rectangular openings, a side wall and a pair of end walls integral with the bottom. A pair of plate retaining blocks are positioned on the bottom midway the sides of each opening and spaced from the edges thereof. Another pair of retaining blocks optionally can be located in spaced relation to the corners of each opening at the end thereof adjacent to the side wall. A plate is slid in over the bottom from the side remote from the side wall and is held in position by the blocks. The end and side walls depend from the bottom and ribs depend from the bottom on both sides to add strength and rigidity to the rack. The underside of the bottom is provided with a plurality and preferably twelve pairs of spaced projections which engage a screw in a viewer to shift the rack laterally for insepction purposes.

United States Patent 1191 Seitz et al.

14 1 Mar. 25, 1975 RACK FOR DIAGNOSTIC DIFFUSION PLATES Primary Eraminer-John H. Wolff [76] Inventors: Lamont J. Seitz, 9302 Candlewood Agent or F.m SC0tt'J' Meyer; LOUIS Dr., Huntington Beach. Calif. 92646; Stephen G. Hauser, 4133 Aleman Dr., Tarzana, Calif. 91356 [57] S y The attached spec1t1cat1on d1scloses a rack for retain- [22] Flled: 1974 ing a plurality of diagnostic diffusion plates in assem- 21] L N 437 07 bled relation The rack preferably is made of injection molded plastic and is of rectangular shape. It com- Related Apphcamm Data prises a bottom formed with a plurality of rectangular [63] Continuation of Ser. No. 297.114. Oct. 19 openings, a side wall and a pair of end walls integral ubandmed with the bottom. A pair of plate retaining blocks are positioned on the bottom midway the sides of each U-S- Cl. R, R, pening and paced from the edges thereof Another Cl. pair of retaining blocks ptionally can be located in Fleld of Search 4O/l06-1- 1 w 64 spaced relation to the corners of each opening at the 40/64 A, 63 158 R, l58 1 159; 220/315 end thereof adjacent to the side wall. A plate is slid in over the bottom from the side remote from the side l l References Clted wall and is held in position by the blocks. The end and UNITED STATES PATENTS side walls depend from the bottom and ribs depend 2,944,356 7/1960 Anthon 40/1061 from the bottom both sides to add Strength and 3,110,120 11/1963 Dunner H 40/79 gidity to the rack. The underside of the bottom is pro- 3.197.888 8/i965 Held 40/64 A X vided with a plurality and preferably twelve pairs of 3. 8. 36 68 M achlan 40/1061 spaced projections which engage a screw in a viewer FOREIGN PATENTS 0R APPLICATIONS to shift the rack laterally for insepction purposes.

436,768 11 /1967 Switzerland 40/1061 6 Cla s, 9 D a ing gu s I 25 j H r||n-- 1 20} 3a l 23 4 10 21 A 2;; 4/

4o l." 39 5 l TE/ 20 Q ,22 23 2i) 40) 24 4 I I n 5 ll 1 ll 3 20 Q i 1 21 24 1 i/so (2 ll 1. 23 22 V 21 1'\ i 111 15 ilill lll'llll" PATENTED 3,872,614

sum? 0F 2 FIG 6.

fins

2 HUI/HIM I j E III I RACK FOR DIAGNOSTIC DIFFUSION PLATES This is a continuation of application Ser. No. 297,114, filed Oct. 12, 1972, now abandoned.

The present invention relates to a rack for diagnostic diffusion plates and is concerned primarily with such a rack that may be disposable and which accepts a plurality of said plates whereby their handling and manipulation is facilitated.

BACKGROUND OF THE INVENTION At the present time, diffusion plates are widely used for diagnostic purposes. Such plates are quite small and are handled with great difficulty and inconvenience. They are of rectangular form with the longer sides frequently having thin external flanges. They are adapted to hold an agar gel material and a diagnostic reagent in which are formed a plurality of wells or recesses in alignment. In use, they are generally placed in an incubator for a prescribed period of time and subsequently inspected to determine the extent or degree of discoloration or diffusion which radiates from each well. The latter operation is carried out with a viewer which desirably would include means for shifting a plate laterally to aid in measuring the extent of radial discolor ation.

While racks have been proposed heretofor for diagnostic diffusion plates, it is believed that the known art is singularly lacking in a rack which may be produced at a cost so low as to permit of disposal and convenient replacement, is made of injection molded plastic, is of a simple rigid construction, will readily accept a plurality of diffusion plates with a simple operation, and includes a device which cooperates with complemental mechanism in a veiwer to laterally shift the rack.

OBJECTS OF THE INVENTION With the foregoing conditions in mind, the present invention has in view the following objectives:

1. To provide a rack which will accept, and retain in position therein, a plurality of diagnostic diffusion plates.

2. To provide a rack, of the type noted, which is produced at such low cost as to render it disposable, if desired.

3. To provide a rack, of the character aforesaid,

which is made of injection molded plastic.

4. To provide, in a rack of the kind described, structure which defines individual compartments each of which accepts and holds in position a plate.

5. To provide a rack, of the type noted, which is sufficiently strong and rigid to withstand the conditions of service usage; and

6. To provide, in a rack of the character aforesaid, mechanism which cooperates with a device in a viewer to laterally shift the rack in the viewer.

Various other more detailed objects and advantages ofthe invention such as arise in connection with carrying out the above objects in a practical embodiment will, in part, become apparent and, in part, be hereinafter stated as the description of the invention proceeds.

SUMMARY OF THE INVENTION The foregoing objects are achieved by providing a rack of injection molded plastic comprising a rectangular bottom having a plurality of rectangular openings therein, a side wall and end walls integral with the bot tom. A pair of plate holding blocks are carried by the bottom midway the sides of each opening and spaced from the edges thereof. Another pair of these blocks optionally can be located in spaced relation to the corner of each opening at the end thereof adjacent the side Wall. Thus, blocks are provided which abut each opening and in effect define a stall or compartment into which a plate may be slid from the side remote from the side wall.

Ribs upstand from the bottom at the entry side of the compartments and cooperate with the blocks in defining the stalls. The side and end walls extend below the bottom and together with depending ribs along the sides of the bottom lend strength and rigidity to the structure. Depending from the bottom at each side are a plurality of channel elements each having an inwardly extending projection that engages the thread of a screw stem of a lateral shifting device of a viewer.

For a full and more complete understanding of the invention, reference may be had to the following description and the accompanying drawing wherein:

FIG. 1 is a top plan view of a rack for diagnostic diffusion plates embodying the precepts of this invention;

FIG. 2 is a longitudinal vertical section of the rack of FIG. 1 being taken on the plane of the line 2-2 of FIG.

FIG. 3 is a transverse vertical section through the rack being taken on the plane of the line 33 of FIG.

FIG. 4 is a detailed section on an enlarged scale through one of the plate holding blocks, being taken on the plane of the line 4-4 of FIG. 1;

FIG. 5 is a detailed perspective depicting a block and a portion of the bottom in assembled relation;

FIG. 6 is a bottom plan view of the rack;

FIG. 7 is a detail on an enlarged scale looking at one of the channel elements from the bottom;

FIG. 8 is a detailed section taken on the plane of the line 88 of FIG. 7 with a portion of the screw stem of a viewer shown in broken lines; and

FIG. 9 is a detail taken on the plane of line 99 of FIG. 8 depicting the screw stem in section.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, a rack embodying the principles of the present invention is designated generally at 10. It is made of injection molded plastic and includes, as a characteristic and essential element, a bottom 11 of rectangular shape presenting side edges 12 and 13 and end edges 14 and 15. Bottom 11 is formed with a plurality of rectangular openings 16, I7, 18, 19, each of which defines a compartment. In this connection, it is noted that the number of openings disclosed is not to be taken as a limitation on the invention as the number may be varied without departing from the spirit and scope of the invention.

Describing one of these openings in detail, each opening 16, 17, 18, and 19 has side edges 20 and 21 and end edges 22 and 23. Each set of side edges 20 and 21 define a transverse panel 24.

Integral with bottom 11 and end edge 14 is an end wall comprising an upstanding portion 25 (FIGS. 1 and 2) and a depending portion 26 (FIGS. 2 and 6). Likewise, an end wall is integral with bottom 11 at end edge 15 and includes an upstanding portion 27 (FIGS. 1 and 2) and a depending portion 28 at each side.

Integral with side edge 12 is an upstanding side wall 29. Integral with the upper edge of end wall portion 27 is a panel 30 from which depends an end flange 31 (FIG. 2). Ribs 32 also depend from panel 30 at each side as shown in FIG. 6. Panel 30 may carry any suitable indicia for display purposes.

Side wall 29 is cut away to provide the four recesses shown at 33 in FIG. 2, each recess 33 being opposite to the end of one of the openings 16, 17, 18, and 19.

Carried by the inner face of end wall portion and midway its ends is a block 34 (FIG. 2), the lower edge of which is spaced from bottom 11, as indicated at 35. This space is dimensioned to accurately receive the external longitudinal flange of a diffusion plate. Another block 36 (FIG. 1) is similarly mounted on end wall portion 25 at its end adjacent to side wall 29.

Projecting inwardly from side wall 29 is a vertical flange 37 which carries on one race a block 38 spaced from bottm 11 as above described and another block 39 on its opposite face. Mounted on the panel 24 which defines one side of opening 16 is a so-called double block 40. One of these blocks is depicted in detail in FIGS. 4 and 5. It comprises a head 41 and a web-like shank 42 which are separated by shoulders 43. Panel 24 is formed wit a pair of slots 44 which are present as an incident to molding block 40 integrally with panel 24. Male and female mold parts are employed in forming each block 40 integral with a panel 24 and having shoulders 43. The male elements of the mold are withdrawn through slots 44. The shoulders 43 are spaced from panel 24 a distance corresponding to the thick ness of a diffusion plate flange as above described.

At one end of the panel 24 referred to above, bottom 11 is formed with an upstanding rib 45 which cooperates with the end of wall portion 25 in marking off a point of entry for a diffusion plate. Thus, a plate may be slid past this point of entry into the compartment defined by blocks 34, 36, 38, and 40. The plate is slid inwardly until its end edge abuts side wall 29. Thus the plate is accurately positioned and secured in this position by the blocks.

The other panels 24 also carry blocks 40 in the same relation above described. Thus, each block 40 provides a shoulder 43 for each compartment 16, 17, 18, and 19. Side wall 29 also has additional flanges corresponding to flange 37 with blocks corresponding to blocks 38 and 39 on its opposite faces. With end wall portion 27 carrying a block corresponding to block 34, each of the remaining openings 17, 18, and 19 is provided with a compartment for receiving a plate in the manner above described.

It will be understood that blocks 36, 38, and 39 are only optional and not essential to the invention.

Referring now to FIG. 6, which may be taken along with FIG. 2, bottom 11 has integrally formed on its underside a plurality of ribs 46 which are spaced along marginal portions of bottom 11 to lend strength and rigidity to the rack. These ribs also serve to maintain axial alignment of the rack when the rack is used in cooperation with screw stem 49 as will be described below.

Depending from the underside of bottom 11 at the end of each panel 24 adjacent to side wall 29 is a channel element 47. Referring now to FIGS. 7, 8, and 9, channel element 47 is formed with a projection 48 any of which extends into the threads of a screw stem 49. The latter is included in apparatus which is used in viewing a plate after incubation for the purpose of shifting the rack laterally.

OPERATION While the manner of using the rack is believed to be apparent from the illustrations of the drawings and description of parts set forth above, it may be briefly outlined as follows:

A plurality of diagnostic diffusion plates are first prepared in the conventional manner. A preferred diffusion plate is one such as described in co-pending application Ser. No. 99,797, filed Dec. 21, 1971. A plate is then inserted in the compartment for each opening l6, l7, l8, and 19. The plates are accurately positioned in the rack and held in these positions with the longitudinal flanges of the plates fitting in the spaces beneath blocks 34, 36, 38, and 40.

The rack is now placed in an incubator for a predetermined period of time. After incubation, it is introduced to viewing apparatus which includes a screw stem 49. As this is accomplished, a projection 48 engages the threads of the stem to allow translation, and ribs 46 and channel elements 47 straddle the stem to maintain axial alignment of the rack. The stem may now be rotated to shift the rack laterally and thus enable the viewer to determine the extent of radial discoloration or diffusion about any well in the plate.

As shown in the drawings (FIGS. 2 and 6), each of compartments l6, 17, 18 and 19 has three pairs of projections 48 adjacent to panels 24 or 30 on the under side of bottom 11. The rack is thereby adapted to ac comodate two embodiments of the diffusion plates disclosed in said co-pending application Ser. No. 99,797. In one embodiment of said co-pending application (FIGS. 1 to 5), the diffusion plate contains one centrally located recess having a row of diffusion wells aligned in the gel whereas in another embodiment (FIGS. 6 to 10) the diffusion plate contains two parallel recesses, each having a row of such diffusion wells. Thus, there are three possible rows of well diameters which are desired to be read in said two diffusion plate embodiments. The three pairs of projections 48 in the rack ofthe present invention allow for placement of the rack on the screw stem 49 in three positions, each corresponding to one of said rows of well diameters. With a diffusion plate having one recess centrally disposed therein, the central pair of projections 48 at each panel 24 or 30 will engage the screw stem 49; whereas with a diffusion plate having two parallel recesses the two outer pairs of projections 48 will be used for engaging the screw stem 48, one pair being used for each recess.

In a preferred embodiment, as illustrated in FIG. 1, the rack is adapted to reading two axes by translating motion of the screw stem 49. An elongated horizontal rib 50 which extends the width of the rack can be provided for that purpose. One or two diffusion plates can then be placed vertically in the rack, one on either side of blocks 40 and positioned lengthwise between end wall 25 and rib 50 for reading diameters parallel thereto. It is thereby possible in operation to read two diameters of the diffusion rings, first by reading one diameter with the plate positioned horizontally as described herein before and then by reading another diameter with the plate positioned vertically. This permits greater accuracy in determining diffusion ring sizes in cases in which the diffusion rings are somewhat oblong instead of true circular. Appropriate calculations for estimating the area of the diffusion ring can then be made by known mathematical formulae.

It is evident that by assembling a plurality, such as four, plates in a rack, they may be handled with more ease and facility, far greater than attends manipulating the plates individually.

While preferred specific embodiments are herein disclosed, it is to be clearly understood that the invention is not to be limited to the exact construction, devices and steps illustrated and described because various modifications of these details may be provided in putting the invention into practice without departing from the spirit and scope of the invention.

What is claimed is:

l. [n a disposable rigid plastic rack for receiving a plurality of diagnostic diffusion plates, each having external longitudinal flanges, said rack comprising:

a. a substantially planar elongate rectangular base presenting side and end edges;

b. a plurality of four elongate rectangular openigns of substantially equal dimensions arranged in side-byside relationship in said base, each of said openings having elongate side edges substantially parallel to the end edges of said base and end edges substantially parallel to the elongate side edges of said base;

c. end walls integral with and upstanding from the end edges of said base;

d. a side wall integral with said base a side edge thereof and including interrupted portions upstanding from said base;

e. an integral and upstanding plate positioning block on said base substantially midway the side edge of each opening and spaced from a side edge of each said opening, said blocks having inner edges spaced from said base a distance substantially corresponding to the thickness of a plate flange; each said block adjacent each opening cooperating with said base to definea compartment adapted to receive one of the plates, each of said compartments having an entry for a plate at the side remote from said side wall;

. integral rib upstanding from said base and which includes one of said plate positioning blocks between the side edges of two adjacent said compartments one of said adjacent compartments being an end compartment; said rib being substantially par- 6 allel to the side edges of said compartments and extending substantially the full length of said side edges; said rib cooperating with said plate positioning blocks to receive two of said plates in side-byside relationship transverse to the side edges of said compartments;

g. reinforcing ribs depending from the underside of said base along portions of the periphery and between the side edges of said compartments which do not have said upstanding rib; and

h. a plurality of pairs of relatively short substantially equally spaced apart ribs depending from teh underside of said base, at least one pair of said ribs being positioned at each of two opposite corners of each said compartments, each of said pair of ribs forming a channel substantially parallel to the side edges of said compartments, and each channel being in alignment with a channel formed by another pair of said ribs at said opposite corner of said compartment whereby the rack by means of these depending ribs is adapted to engage a shaft mechanism on a cooperating diagnostic plate viewer.

2. The rack of claim 1 in which each opening is partially defined by transverse panels and certain of said blocks which are located substantially midway the side edges of the openings take the form of double blocks upstanding from said panels.

3. The rack of claim 2 in which each double block comprises a head and a shank separated by a pair of shoulders on opposite sides of the head, and the shank is secured to a panel with the shoulders spaced therefrom.

4. The rack of claim 3 in which the shank of each block is integral with a panel and a slot in said panel on each side of said shank.

5. The rack of claim 2 together with an upstanding rib on the said base opposite to each panel and on the side remote from the side wall, said ribs and end walls cooperating to define said entry.

6. The rack of claim 1 in which each channel on one side of said rack is provided with an oblique, downwardly depending projection at the outer edge of, and

between the pair of ribs forming, said channel. 

1. In a disposable rigid plastic rack for receiving a plurality of diagnostic diffusion plates, each having external longitudinal flanges, said rack comprising: a. a substantially planar elongate rectangular base presenting side and end edges; b. a plurality of four elongate rectangular openigns of substantially equal dimensions arranged in side-by-side relationship in said base, each of said openings having elongate side edges substantially parallel to the end edges of said base and end edges substantially parallel to the elongate side edges of said base; c. end walls integral with and upstanding from the end edges of said base; d. a side wall integral with said base a side edge thereof and including interrupted portions upstanding from said base; e. an integral and upstanding plate positioning block on said base substantially midway the side edge of each opening and spaced from a side edge of each said opening, said blocks having inner edges spaced from said base a distance substantially corresponding to the thickness of a plate flange; each said block adjacent each opening cooperating with said base to define a compartment adapted to receive one of the plates, each of said compartments having an entry for a plate at the side remote from said side wall; f. integral rib upstanding from said base and which includes one of said plate positioning blocks between the side edges of two adjacent said compartments one of said adjacent compartments being an end compartment; said rib being substantially parallel to the side edges of said compartments and extending substantially the full length of said side edges; said rib cooperating with said plate positioning blocks to receive two of said plates in side-by-side relationship transverse to the side edges of said compartments; g. reinforcing ribs depending from the underside of said base along portions of the periphery and between the side edges of said compartments which do not have said upstanding rib; and h. a plurality of pairs of relatively short substantially equally spaced apart ribs depending from teh underside of said base, at least one pair of said ribs being positioned at each of two opposite corners of each said compartments, each of said pair of ribs forming a channel substantially parallel to the side edges of said compartments, and each channel being in alignment with a channel formed by another pair of said ribs at said opposite corner of said compartment whereby the rack by means of these depending ribs is adapted to engage a shaft mechanism on a cooperating diagnostic plate viewer.
 2. The rack of claim 1 in which each opening is partially defined by transverse panels and certain of said blocks which are located substantially midway the side edges of the openings take the form of double blocks upstanding from said panels.
 3. The rack of claim 2 in which each double block comprises a head and a shank separated by a pair of shoulders on opposite sides of the head, and the shank is secured to a panel with the shoulders spaced therefrom.
 4. The rack of claim 3 in which the shank of each block is integral with a panel and a slot in said panel on each side of said shank.
 5. The rack of claim 2 together with an upstanding rib on the said base opposite to each panel and on the side remote from the side wall, said ribs and end walls cooperating to define said entry.
 6. The rack of claim 1 in which each channel on one side of said rack is provided with an oblique, downwardly depending projection at the outer edge of, and between the pair of ribs forming, said channel. 